Hi
Are you sure that you have installed right LAN driver?
It seems that Toshiba does not provide drivers for Win 7 for this notebook model…
Did not find Win 7 drivers on the European driver page so I assume you need to search for the driver at your own hand.
As far as I know the notebook supports an Realtek LAN card.
I recommend visiting the Realtek driver page and to download the LAN driver directly from chip manufacturer page.
http://www.realtek.com.tw/downloads/downloadsView.aspx?Langid=1&PNid=7&PFid=10&Level=3&Conn=2
Additionally you could try this one released for Satellite Pro A200 series since this model seems to be equipped with the same LAN card:
Realtek LAN Driver V 7.003.0522.2009